help i've fallen
by owlady
Summary: "AND I CAN'T GET OUT." A spiky skeleton falls asleep during guard duty and wakes up to something weird. Thing is, even though it sounds like a joke neither him or the heroic skeleton can figure out the punchline. Underfell, Underswap, genfic. Rated for some language.
1. Chapter 1

Well. It was official.

Sans fell asleep on guard duty.

His fault. Sure, he always felt tired, but he knew better than to catch a nap when he was supposed to be looking out for humans. Not that he cared about catching a human, because the chance he'd actually see one were slim to nil, but he definitely cared about the way it made his brother look when it came time for post inspections.

If Sans dozed off, it looked like Papyrus couldn't keep his underlings in line. And if Paps couldn't do that, then of course he just wasn't strong enough to do so. Which was bad. Because in a world of kill or be killed, being weak got you dusted.

The harder Sans worked, the less chance someone would take a potshot at Papyrus. That was just how things ended up. Papyrus might lecture too much, might be a little too obsessed with humans, but he was still Sans' brother. They looked out for each other.

"yeah, that's my boss. ain't he cool?" He'd grind out to some uppity dog, his only eye blazing red in its socket. "he'd dust you without thinkin' twice. mebbe you oughta back off, jus' sayin'."

In return, Papyrus would take the heat off of him, best he could. Sans still had to work to be intimidating, still had to try to even care, but it wasn't crushing when his bro could just stalk in and fire a precise three bones, screeching, "SANS, YOU LAZYBONES. YOUR DEATHTRAPS ARE PITIFULLY SUBSTANDARD! IF I FIND YOU'VE BEEN DELAYED BY ANOTHER MONSTER-"

It was strange to have real allies down here. Everyone operated by looking after themselves in New Home. Maybe that was why Sans and Paps actually had a house instead of a hovel or a hotel room- two boneheads were better than one.

Of course, it wasn't without its risks. Had to keep up appearances, never got to really sleep, the mustard was substandard. It was exhausting. Incredibly, ridiculously exhausting. Training on top of that was impossible. Maybe he shouldn't have actually tried, but giving up hadn't seemed like an option when Paps was going at it for hours before Sans had even started. It just made him feel... bad. Not good. It made his hands shake and his brow sweat, because Paps was under the same pressure Sans was and yet he could _do_ this while Sans didn't even want to try. What did that make him? A quitter? What would happen if he just stopped, just quit trying?

The more Sans had thought about it, the sweatier he had got, the faster his soul had felt like it was beating out of his chest. There was something ugly and raw that he hated inside himself, and not trying made it worse. Even if some days, he wanted to give up. So every day, he tried. Even if it was tying his shoes, or not falling asleep during sentry duty, or actually pulling his weight and working his shifts at the Hot Cat stand down in Hotland instead of trying to cheat his way through the day.

But today, one of his 'don't fall asleep' days, he'd passed out. Because yesterday when Paps had offered to train with him, that tight feeling in his chest and that feeling of terror when contemplating saying no hadn't let him refuse. Souls, he was tired after grinding EXP. And it had been so quiet, snow muffling everything. No humans, no monsters, just pine trees and freshly fallen artificial precipitation.

Sans had fallen asleep.

That feeling of failure permeated the air around him as soon as he woke up. Sans knew what had happened, had to resist the urge to drag his claws down his skull. His breathing was wheezy until he snarled and got up, looking around. There wasn't any use in crying over spilt monster candy, not when someone could have seen him while he was asleep. His left hand crawled up, tracing the crack along his skull, wiping new sweat away. Souls, this again? This was bullshit. So he fucked up. That didn't mean he had to fall to pieces.

Sans' breathing didn't get any easier. There was just a sense of fear and anger that made breathing hard and sweating easy.

Sans didn't see much. It was still snowing, collecting on his parka and covering any evidence a monster had been here at all. Sans almost thought that maybe he'd been paranoid. Maybe karma had liked Sans just this once, decided to give him a break because he needed the sleep.

And then he noticed that some of the footprints on the ground he'd assumed were his own _weren't_.

They were the same size and shape, but while Sans' sneakers left marks in the snow from his spiked cleats, there was another line of prints with horizontal lines across the foot and heel. Like hiking boots.

 _Shit._

Shit, fuck, shitfuck. Damn.

Sans had to find whoever saw him slacking off. If they hadn't dusted him while he was sleeping (another reason not to sleep during duty) they'd definitely go after his brother, Papyrus.

Shaking the snow off, Sans followed the prints. His ever-active magic eye could tell whoever had seen him had had low LV, but pretty decent magic. Probably Sans' size and weight, too. Judging by the lack of disturbance in the tracks, no fur. No fire, either. What kind of monster was this? Could've been Alphys, but she didn't leave her lab anymore. Too dangerous, lotta risk of getting dusted.

Sans kept following the tracks, occasionally taking a shortcut when there was a stretch of snow or a gap he couldn't pass because nobody had repaired the outer Snowdin bridges. Pretty soon he was near his brother's human traps, or what other members of the guard called 'Deathtrap Mountain'.

It was literally a mountain of traps. Spiked balls, mousetraps, flamethrowers, dogs tied to beartraps that said 'FREE DOG' on them. All stuff that Paps assumed would both entice a human and dust them so that Papyrus could collect the soul and finally become captain of the guard.

Only DTMN wasn't looking so death-trap anymore. Someone had thoughtfully capped all of the flamethrowers, tied up the bear traps, freed the dogs, and put little corks on all the spikes of the spiked balls. The mousetraps were simply in a little stack on the ground.

And the tracks ended here.

"what," Sans asked aloud, with a sizable pause in the middle, "the fuck."

Was someone actually pulling a prank on Papyrus? Had they seen Sans sleeping and decided that Papyrus wouldn't come after them if they pulled a joke because he hadn't come after his brother for not doing his job?

...not doing his job.

Shitfuck!

Sans felt a bead of sweat gathering. Nope. Shit, he just abandoned his post. Didn't even know what time it was. He had other shifts to think about. Couldn't exactly abandon his job in a world where people dusted you for not trying-

Sans spun on one heel. Nope. Ha, ha. Can't deal with this. Sans had to get back to his post and his job. It was all he could handle before something in him gave out. No extracurriculars for this skeleton. It wasn't _school_ to ditch your seat.

...man, did Sans say that one out loud?

"THAT WAS TERRIBLE!"

OH, SOULS!

Immediately, bones erupted from the ground, Sans' eye blazing like fire as he instinctively grabbed for a soul with blue magic and tried to forcibly combine the two.

"EXCUSE YOU!" The same voice reprimanded him, suddenly gone from where it had been. Sans looked around, turning his head so he could see everything with his one eye-

...someone had to be messing with him.

"DID I STARTLE YOU? I DIDN'T MEAN TO, OF COURSE, BUT THE AMAZING AND **BOLD** SANS SOMETIMES FRIGHTENS MONSTERS WITH HIS MERE PRESENCE," A skeleton rattled at him, dressed in some kind of... sentai suit? With blue boots and a blue bandana tied around the skeleton's neck. "I WANTED TO APPROACH YOU SOONER, BUT YOU WERE SLEEPING HARD. AND MOST SANS DON'T APPRECIATE BEING WOKEN UP."

It was a clone. There was a pudgy, smiling, friendly clone standing right there in front of him, holding out a gloved hand for Sans to shake.

"SO I DECIDED TO WAIT. DID MY USUAL FIVE MILE MORNING JOG, AND THEN I SAW THIS MESS AND THOUGHT I COULD HELP CLEAN IT UP. HELLO! I'M SANS, SANS THE SKELETON," the clone said, his grin ever-present. Unlike Sans' (the original, not the happy blue faker) teeth, this guy's were straight. It made him look even more harmless. "AND I THINK I TOOK A WRONG TURN AT THE SPACE-TIME CONTINUUM. DO YOU KNOW THIS UNIVERSE'S IDENTIFICATION NUMBER?"

Sans replied in the sanest way any monster could when confronted with a happy, active version of themselves that seemed to shout instead of talking. In his mind, it was very reasonable to do what he did. Sans had to find Paps and let him know about new monsters appearing out of nowhere.

"...fuck this shit, i'm out."

He took a shortcut and left the little blue freak in the woods for someone else to dust.

* * *

AN: Possibly a oneshot? It depends if I figure out how this plot bunny would even work out.


	2. Chapter 2

Like most of Sans' shortcuts, this one left him dizzy. Feeling a little sick. It used to be easier for him to do a shortcut, but since he'd been forcing himself to practice more often, it had gotten harder and harder. But at least he'd left that blue guy behind. Sans just knew if someone saw the clone, they'd kill it and then come after him. It was an affront to both Sans and Papyrus for that blue thing to exist, especially when they'd worked so hard to get a safe house and Paps a job in the royal guard.

Leaning against the wall of the shed outside of their Snowdin house, Sans decided that the most likely culprit was Alphys. She was supposed to be working with determination, but given her twisted sense of science there was a chance she could have gotten her claws on a bone sample from him. After all, he fought plenty. There was lots of places she could have found a chip or two.

Right now, Sans needed a nap. But he couldn't nap, because today he wasn't supposed to nap and he'd already broken one of his personal rules. Couldn't hand the bad times from that any more. Maybe he could get a hot cat, but that was optional. He'd already left his post, having fallen asleep, and with the looming threat of a blue puffball on the horizon... Sans figured if he was given a shit dime, he'd be in for the whole shitty dollar.

He reached into his pocket, flipped his phone open... and just stared at it as he made his way up the stairs to his room, avoiding the carefully staged Sock War that his brother had set up to demonstrate attack plans should their house ever come under siege. Paps' sock was a christmas stocking. Sans' was half a red sock with a ripped toe. The rest of the monsters were tube socks.

Sans really hated tube socks. Assuming the blue guy stuck around, they'd have to add another one to Paps' little war game.

His clawed fingertips traced over the one on his phone. Why was he having such a hard time making this decision? Either he told Paps about the faker or he didn't. Either way he was going to have a great time dealing with the inevitable aftermath. It would probably involve food, bandages, and dusting an annoying monster with a huge mouth. ...man, did killing your own clone count as homicide, or suicide?

Sans didn't know. He flipped his phone shut and traded it for his door key, which was unceremoniously shoved into the knob and turned to reveal-

Sans' room. Just how he left it, really.

Except it was clean. Which wasn't how he left it at all. All of his trash (the kind that didn't have important notes on it) was piled neatly in the corner. There was a rope around the trash cyclone's neck, which was keeping it happily contained to stirring up said corner-trash pile. His mattress had been shoved back up against the wall, and his own collection of socks and extra clothes had been designated their own space at the foot of it. What was probably the weirdest was that all of his Quantum Joke books, volumes 1 through 3, Extra Dark Matter Humor editions were neatly on display on what Sans could only call... a desk? It was really just a board on top of some more of the junk in his room.

Sans hadn't looked at a Quantum Joke book in years. They had been shoved under his bed and forgotten as soon as Paps got into the guard and he got assigned to be a sentry.

"What do you call an apathetic mass," Sans read, taking one down and opening it. "Doesn't matter."

The blue clone had been here already. And he'd dug around in Sans' stuff, which was worse.

Sans heard a door slam. He jumped and the joke book fell to the ground, opening to a new page, a new joke. What do you call a guy on a slope helically wrapped around an axis?

Screwed. Sans was so screwed.

Paps was home ( _could_ be home, some rational part of his brain tried to argue) and some stranger had obviously been in their house, because Sans would never clean his room. He just didn't have the energy after working three jobs and still making time to train with his brother. They'd have to change out the locks, Paps would have to fight with him in public to reinforce the idea that he was a complete hardass that nobody should stand up against, and Sans would get extra shifts. No more extra training for him.

There was no reason to panic, but Sans was doing it anyway. Quietly.

Sans rushed out, not bothering to lock the door as he took a shortcut into the kitchen, sidling up against the wall. He tried not to breathe loudly, but even short shortcuts could leave him out of breath. Sweat slipped down his skull. His red eye flickered until he made it blaze again.

Sans had to go face the music.

He took a deep breath and walked out into the living room, a 'Hey, Paps' on the tip of his tongue when he saw it again.

The blue clone.

And it was PICKING UP THE SOCK WAR.

Sans didn't even realize he'd taken a shortcut until he slammed into the other, a fresh bone pressed like a knife against the clone's neck. More sweat poured off of him. It came back here. That meant that it had some way to get in. It had done it at least twice, assuming the damn thing hadn't just taken a shortcut to get inside in the first place.

"HEY," the clone complained. Sans ignored him, ready to dust. "IS THAT ANY WAY TO TREAT THE AMAZING COOK, SANS?"

...cook?

All it took was a moment's hesitation. Confusion. As soon as his bone wasn't close enough to kill, the blue faker grabbed waist, spun, and suplexed him.

The impact left his skull rattling. What the hell? What the actual hell?

"CAPTAIN ALPHYS TAUGHT ME THAT," the blue faker said proudly. Sans remained on the floor. "I DECIDED THAT WE SHOULD BE FRIENDS, AND THE BEST WAY TO MAKE FRIENDS IS TO SHOW THEM YOUR PASSION!"

Sounded like Undyne, to Sans. But the faker had just mentioned Alphys. Alphys being a captain? Had she been promoted to something else by the king, commissioned to make this obscenely happy... thing? How could a clone of him EVER be this cheerful?!

"SO, TRAINING! CHECK," The clone said, making a little check mark in the air. "ORGANIZING THINGS! CHECK. I THINK YOU'LL BE VERY HAPPY WITH YOUR ROOM WHENEVER YOU SEE IT NEXT. AND COOKING!" The blue thing paused, looking sheepish. "...NOT QUITE CHECK. BUT REST ASSURED, I'M GOING TO MAKE THE BEST MAC AND CHEESE YOU'VE EVER TASTED, OR I'M NOT THE MAGNIFICENT AND BOLD SANS!"

Oh, hell.

Sans' skull really... really hurt. "fuck," he mumbled. The room was spinning. Hadn't done that since the last time Sans had overdone it training. Which was yesterday. He'd ended up fainting yesterday. Paps'd yelled at him, n' then he'd fallen asleep this morning...

"YOU REALLY SHOULD WORK ON THAT BAD HABIT," his clone admonished him. "WHAT IF KIDS WERE READING THIS?"

What was he even talking about.

"what the fuck," Sans concluded. He barely noticed the grocery bags spilling out onto the floor. The blue guy must've dropped them. He had just ditched the clone- when had he gotten a chance to buy any?

And then he passed out.

* * *

I guess I'm writing more of this? It's honestly pretty fun. Underfell was created originally by the underfell blog on tumblr, and underswap was created by popcornpr1nce over there, too. This story is just my interpretation of ideas for some fun. Thanks for reading!


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